#include <iostream>
using namespace std;
#define int long long
const int N = 88;
int f[N];
 
signed main()
{
    f[1] = 1, f[2] = 1;
    int left = 0, right = 0;
    for(int i = 3; i <= N; ++i)
    {
        f[i] = f[i - 1] + f[i - 2];
    }
 
    while(cin >> left >> right)
    {
        int res = 0;
        for(int i = left; i <= right; ++i)
        {
            res += f[i];
        }
        cout << res << endl;
    }
    return 0;
}